I want to setup a captive portal where in first time users will have to register first before using the internet and existing users have to login. There are many captive portals out there and I think I'm gonna try pfsense or monowall. My question now is what software do I have to use for the registration and authentication process mentioned above? I have read that a RADIUS server can be used but is there one out there where it would accept user registration so that they can log in and authenticate to be able to use the internet?